The Study On The Mechanism In Purification Of Diatomite Ore By Microwave Strengthening

The main trend in modern non-metallic mineral industry is deepening processing for minerals and production of these products. It is one of new methods on mineral deepening for using microwave technology to purify diatomite .We decided on adopting diatomite in this paper, performing "the study on the mechanism in purification of diatomite ore by microwave strengthening" then probing into the regular patterns on purification of diatomite processing by microwave strengthening.The results of the experiment indicated that temperature of diatomite ore and water and diluted sulfuric acid solutions would raise in microwave field. We found that raising temperature of diatomite is different from that of pure metallic minerals, has not "getting out of control " phenomenon; raising temperature process of diatomite in microwave field can be divided into two stages ie. linear raising temperature period and logarithmic one, and can be described by onespot third order multinomial. Raising temperature behavior of water and sulfuric acid solutions in microwave field can be described by onespot second order multinomial. Investigation found that the conductivity of water and diluted sulfuric acid solution both are higher than conductivity in conventional condition and microwave has a "non-heating effect" for water and diluted sulfuric acid solutions.The results of the researches on the mechanism on purification of diatomite ore by microwave strengthening indicated that conductible current in diatomite particles was formed and electrons were accumulated under electromagnetic fieldaction, this is advantageous to overcome the width of forbidden band; particles or solution ions in pulp system take place turn and orientation polarization, therefore promote electrons exchange and reaction; at same time, microwave can result in mineral particles cracking, specific surface area rising, reagents entering interior of mineral particles, increasing reaction opportunity, raising conductibility of liquid matter in reaction system , raising pulp temperature, and promoting reaction going on.Based on theory and experiment research, kinetic model of isothermal stable state reaction of acid leaching purifying for diatomite was established.Microwave:Conventional :There, T is reaction temperature, K; x is leaching rate of iron from diatomite,% ; t is reaction time, s; R is molar gas constant, 8.314 J/(mole. K).Activation energies of chemical control for microwave action and conventional heating action are 59.05 KJ/mole and 28.49KJ/moIe respectively, frequency factor ratio Kmic/Kconv=77049.24. Activation energies of mixed control for microwave action and conventional heating action are 111. 09 kJ /mol and 64.63 kj/mol respectively, Under microwave field action, activation energy of chemical reaction increased, but frequency factor greatly increased, microwave field has influenced on reaction system by depressing and promoting and increased chemical reaction rate last. The results of the experiment indicated that the reaction velocity of microwave reaction is 3-10 times with that of conventional heating reaction.The study on non-isothermal leaching process was performed with industrial production, kinetic equation of acid leaching purifying for diatomite was established.there n=2/3; E or E' is activation energy, J/mole; x is leaching rate of iron from diatomite, %; T is temperature in reaction system, K; w is microwave interaction power, W; A is frequency factor; is raising temperature rate ;a and b are temperature constants related with microwave power ,w.The investigation has indicated that raising temperature rate of reaction system with microwave is a function of time, the relationship between raising temperature rate and temperature is nonlinear; and has found that the influence of microwave on chemical reaction is a non-linear relationship. Activation energy and factor of reaction can be changed by microwave interaction, and decreased along with microwave power increases, after reaching to a certain degree, they raise.A new technology for purificati...